This FM Transmitter kit provides two transmitting frequencies set by the two crystals provided.
You can use other crystals to transmit on other frequencies.
Increase your range with this amplifier kit: QK171
This project is a complete crystal-controlled Wide Band Frequency Modulated (WBFM) transmitter
delivering a power output in the order of 10 milli-watts (+10dBm) using simple components. The
transmitter is based upon the Phase-Locked Loop (PLL) principle, but due to the circuit's simplicity a
true "phase lock" can never be achieved.
The transmitter has both 1v peak-to-peak 'LINE' input and 10mV 'MIC' audio inputs. These will
accept audio input sources from external equipment, such as hi-fi, CD and computer equipment. The
microphone input also has an in-built power source to energize an 'Electret' type condenser
microphone.
The Radio Frequency (RF) output circuitry includes a three-pole filter for reduction of harmonics and
other spurious signals. The spurious output signal level is better than -40dBc (0.0001 times the power
of the wanted signal level), which makes the project suitable for driving an external power amplifier.
The transmitter is powered from a 12v supply, but it will operate from 9 Volts to 16 Volts. The DC
power input is equipped with a diode (D1), which protects the transmitter in the event the supply
voltage is inadvertently connected the wrong way round.
QK172 Documentation in PDF format
Validate your login
Sign In
Create New Account